Implement canvas focus ring methods.

Source/core/html/canvas/CanvasRenderingContext2D.h

Index: Source/core/html/canvas/CanvasRenderingContext2D.h
diff --git a/Source/core/html/canvas/CanvasRenderingContext2D.h b/Source/core/html/canvas/CanvasRenderingContext2D.h
index 6ec45255d8cde044981148bb38ec7cd9081a67ee..80b91bc19b73cca94dde2178ca009201d88636f1 100644
--- a/Source/core/html/canvas/CanvasRenderingContext2D.h
+++ b/Source/core/html/canvas/CanvasRenderingContext2D.h
@@ -48,6 +48,7 @@ class CanvasGradient;
 class CanvasPattern;
 class CanvasStyle;
 class DOMPath;
+class Element;
 class FloatRect;
 class GraphicsContext;
 class HTMLCanvasElement;
@@ -226,6 +227,9 @@ public:
 
     PassRefPtr<Canvas2DContextAttributes> getContextAttributes() const;
 
+    void drawSystemFocusRing(Element*);
+    bool drawCustomFocusRing(Element*);
+
 private:
     struct State : FontSelectorClient {
         State();
@@ -321,6 +325,10 @@ private:
     PassRefPtr<ImageData> getImageData(ImageBuffer::CoordinateSystem, float sx, float sy, float sw, float sh, ExceptionCode&) const;
     void putImageData(ImageData*, ImageBuffer::CoordinateSystem, float dx, float dy, float dirtyX, float dirtyY, float dirtyWidth, float dirtyHeight, ExceptionCode&);
 
+    bool focusRingCallIsValid(const Path&, Element*);
+    void updateFocusRingAccessibility(const Path&, Element*);
+    void drawFocusRing(const Path&, Element*);
+
     virtual bool is2d() const OVERRIDE { return true; }
     virtual bool isAccelerated() const OVERRIDE;
     virtual bool hasAlpha() const OVERRIDE { return m_hasAlpha; }